1. Field of the Invention
The present invention relates to the use of ozone to treat and process aqueous waste feedstream, especially as this would relate to treatment at filtration plant facilities; but also in other uses, where the concern or object exists to improve flux rates of feedstream through filter media and effectively change feedstream character so that it is presented in a condition where it will cause less wear or destruction of such media, and provide the added feature of effectively cleaning such filter media.
2. Background Information
It has been determined in the art that Ozone kills many biological agents by oxidizing the organic molecules that form the cell surface and in dealing with the problem of calcium buildup (a major portion of total dissolved solids—TDS), as well as dealing in the past with biocides used to chemically treat water systems.
Those references found which appear to have at least some relationship to the technology of ozone treatment and processing of environmentally significant aqueous waste feedstream including the fllowing: Williams, et al., U.S. Pat. No. 6,183,646; Crisinel, et al., U.S. Pat. No. 6,162,477; Foellmi, U.S. Pat. No. 6,074,564; Shultz, U.S. Pat. No. 6,001,247; Faivre, et al., U.S. Pat. Nos. 5,843,307 and 5,271,830; Busch, Jr., U.S. Pat. No. 5,807,486; Tempest, Jr., U.S. Pat. No. 5,741,416; Bhave, et al., U.S. Pat. No. 5,645,727; Dickerson, U.S. Pat. No. 5,397,480; Ditzler et al., U.S. Pat. No. 5,114,576; Engel et al., U.S. Pat. No. 5,097,556; Cole, et al., U.S. Pat. No. 4,849,115; Hiltebrand, et al., U.S. Pat. No. 4,622,151; Cohen, et al., U.S. Pat. No. 4,595,498; and Johnson, et al., U.S. Pat. No. 4,200,526.
Also having some relevance in terms of discussing some of the chemical principles involved in the present invention's technology (such as solubility aspects, pressure and the application of the Laws of Boyle, Charles, Dalton and Henry, and other chemical aspects), are the following references: (1) Various editions of Lange's Handbook of Chemistry, setting forth the “Solubility of Gases in Water,” particularly as this relates to Oxygen and Air into Water or Water and Solvents; (2) Graik, et al., 2001, “The Effect of Ozone Gas-Liquid Contacting Conditions in a Static Mixer on Microorganism Reduction,” Ozone Science & Engineering, Vol. 23, pp. 91-103; (3) Min Cho et al., 2001, “Effect of pH and Importance of Ozone initiated Radical Reactions In Inactivating Bacillus subtilis Spore,” Ozone Science & Engineering, Vol. 24, pp. 145-150; (4) Mortimer, C. H., 1981, “The oxygen content of air-saturated fresh waters over ranges of temperature and atmospheric pressure of limnological interest,” International Association Of Theoretical And Applied Limnology, pp. 1-23, E. Schweizerbart'sche Verlagsbuchhandlung: Stuttgart; (5) Langlais, et al. (eds.), 1991, Ozone In Water Treatment Application and Engineering, pp. 90-132, 349-442, 474-485 and 543-551; (6) Masschelein, W. J. (ed.), 1982, Ozonization Manual for Water and Wastewater Treatment, pp. 47-56, 69-102, 129-139, and 151-153, John Wiley & Sons: New York; (7) Gerrard, w\W., 1976, Solubility Of Gases and Liquids, pp. 1-276, Elsevier Scientific Publishing Company: New York; (9) Lide, D. R. (ed.), 1995-1996, “Vapor Pressure Of Fluids At Temperatures Below 300K—Ozone (O3)”, CRC Handbook of Chemistry and Physics, p. 6-71, CRC Press: New York; and (10) Linke, W. F., 1965, “O3 Ozone Solubility In Water,” Solubilities Inorganic and Metal-Organic Compounds, pp. 1239-1240, American Chemical Society: Washington, D. C.
The Faivre et al. '307 and '830 patent references would appear to be the closest potentially applicable prior art. The '307 reference is entitled: “Unit for the treatment of water by ozonation, and a corresponding installation for the production of ozonized water.” The '830 reference is entitled: “Water treatment installation for a tangential filtration loop.” These references teach a water treatment unit and installation designed expressly for the purpose of producing “ozonated white water,” or water characterized by a multi-phase, non-homogeneous mixed system containing gaseous “bubbles” of ozone within the water, giving the water the appearance of turbulent ‘white’ water, and disclosed to have bubbles the size of between 20 and 200 microns, or larger in magnitude by virtue of the visibility to the naked eye of bubbled white water as described in Faivre.
The bubbles and white water of the Faivre teachings are designed to create physical turbulence in the water at the membrane, and employ the ability of ozone, in such a gaseous state, as an oxidation agent to further restrict clogging of their tangential filtration membrane. Such installations or units require a reduction in initial pumping pressure to form gaseous ozone bubbles, and a phase separation to prevent cavitation of pumping units and other equipment on line by virtue of Faivre's feedstream being at a point of supersaturation with the presence of potentially damaging gaseous bubbles; therefore, exposing such a system to the loss of useful ozone content, even in the form of the gas bubbles earlier created, as well as further time and expense in reinstating gaseous ozone bubble concentrations with regard to any recycling operations. The pressure in the Faivre installation must be dropped some 50% to 75% before reaching any filter unit to form Faivre's ozone gas bubbles. The unit or installation system of Faivre cannot sustain useful pressure throughout its system loop, from beginning to end, during any given cycle of its application or operation. This loss in pressure will decrease potential flow rate across tangential membranes along with significant reduction in turbulence. Nor can it recycle, as indicated, without losing its gaseous ‘white water-bubbled ozone and starting from the beginning in re-generating its gaseous ozone bubbles or white water. These systems, therefore, lose their ability to effectively clean filter media because gaseous bubbled ozone, multi-phase fluid or suspension is submitted not to be an optimal form for effectively cleaning and saving wear on filter media. Nor is it effective and cost-saving in re-utilization through re-cycling because of the required reduction in pressure to form ozone bubbles and the phase separation required to protect against cavitation and other phase separation damage to pumps and other such equipment within Faivre's loop, or other equipment utilized on-line. This is born out by its relative or substantial obscurity of use in any environmental system employing filter media in the United States. Additionally, the teachings of Faivre would suggest, chemically, that its unit, installation or system, is sensitive to temperature and pH requirements because of the nature of its gaseous multi-phase mixture; thereby inherently involving greater potential for failure or demanding greater time and expense to maintain.
These and other disadvantages, structurally, functionally and by virtue of distinction in process and method approach, will become apparent in reviewing the remainder of the present specification, claims and drawings.
Accordingly, it is an object of the present invention to provide a substantially improved and cost-effective method in treating aqueous waste feedstream for improving the flux rates, cleaning and prolongation of useful life of filter media in many diverse environmental and process applications; with special adaptability and advantageous application to aqueous feedstreams from nuclear plant sites.
It is a further object of the present invention to provide a method which utilizes the solubilizing (or the making soluble and uniform) of an ozone mixture (provided as having at least O3 and O2) and an aqueous feedstream to create a substantially homogeneous single phase liquid mixture or a substantially homogeneous molecular single phase mixture, without ‘white water’ or ozone bubbles; so that the ozone mixture generated within the present process and the aqueous feedstream to which it is applied are dissolved and miscible, one with the other, at a level below the saturation point of the generated ozone mixture (rather that at point of supersaturation); thus making it a more active and concentrated ozone solution system (with greater oxidizing power and cleaning ability).
It is yet a further object to provide a system and process of dissolving and solubilizing ozone in an aqueous feedstream to produce a substantially single phase liquid system which will not damage filter media, pumps and like units on-line; and which can be maintained at a desired or higher pressure throughout the system on-line, from the beginning to the end of a complete given cycle, for maximizing the positive effect of the concentrated active oxidation or oxidizing power of such a single phase liquid system on a filter media; through enhanced cleaning, improved flux rates, improved quality and volume amount of effluent permeate, and the ability to recycle reject volumes for further cleaning and oxidation exposure without having to lower the pressure on-line.
It is a further object of the present invention to provide a solubilized ozoneaqueous feedstream system which will have greater ozone concentration and oxidation activity at the surfaces of filter membranes or other filter media surfacing, for improved cleaning and prolonged useful life; while also serving functionally to cost-effectively facilitate greater amounts of permeate, faster re-cycling rates and greater volume movement potential throughout the system in relation to time.
It is yet a further object of the present invention to provide a method and system which will operate well at various pH and temperature ranges or ambient conditions at a given site.
It is an additional object of the present invention to sustain a workable higher pressure above atmospheric pressure throughout the on-line system and installation constituted in accordance with the present invention, to achieve the most optimal concentration and resulting activity of ozone in solution with an aqueous feedstream so that the full advantages of utilizing ozone to clean and prolong the life of otherwise expensive filter media are realized in that:                (1) Since ozone is generated by an electrical discharge into oxygen (supplied as plant air), no handling of hazardous chemical is required, with a flip of a switch beginning ozone production;        (2) Ozone has a much higher oxidation potential than hypochlorite (free chlorine) or hydrogen peroxide, which means that it reacts faster and attacks organics at a much higher rate;        (3) Ozone decomposes to oxygen, so no chemical contaminants (e.g., sodium chloride or chloramines) will affect downstream ion exchange performance or capacity;        (4) Ozone has a half-life of approximately 20 to 30 minutes, so there is no credible scenario for it to be found in plant effluent; and        (5) Ozone dissolved in water is less aggressive to Tubular Ultra Filtration, Cross-Flow Membrane Media or other filtration means or units than hypochlorite or like chemicals or substances. Therefore, the use of ozone can enhance membrane life and reduce membrane fouling and frequency of cleaning, while maintaining a higher flux rate.        
It will, therefore, be understood that substantial and distinguishable process and functional advantages are realized in the present invention over the prior art; and that the present invention's efficiency and adaptability of operation, diverse utility, and broad functional applications serve as important bases of novelty and distinction in this regard.